1. Field of Invention
The present invention relates to a flame-retarded acrylonitrile-butadiene-styrene composition containing bis(2,4,6-tribromophenoxyethyl)tetrabromobisphenol A ether.
2. Description of the Prior Art
Acrylonitrile-butadiene-styrene ("ABS") thermoplastics offer a good balance of physical and mechanical properties such as good abuse resistance, heat resistance, moldability, stain resistance, chemical resistance, and surface hardness. Because of their properties and their moderate cost, they have been chosen for use in a wide range of applications. They are used by telephone and automotive manufacturers who require materials with high impact strength. Manufacturers of boats utilize these materials because of their high strength-to-weight ratios and their deep draw thermoformabilities. Manufacturers of luggage, appliances, sporting goods, safety equipment, and toys utilize these materials because of their light weights and their flexural and high impact properties.
ABS plastics are derived from acrylonitrile, butadiene, and styrene. The general chemical structure for these plastics is ##STR1## wherein x, y, and z (which may be the same or different) are from about 10 to about 1,500. Some of the properties of typical ABS plastics are described on pages 1-64, 1-66, and 1-68 of Charles A. Harper's "Handbook of Plastics and Elastomers" which was published by the McGraw-Hill Book Company in 1975; these pages are hereby incorporated by reference into this application.
ABS plastics are widely used by manufacturers of business machines, building components, television components, and institutional products. For many of these uses the ABS plastic must be flame-retarded.
Many flame retardants have been described by the prior art. Some relevant prior art references which describe such flame retardants include, e.g., German Pat. No. 2731817 (which describes a bromobisphenol ether fireproofing agent); Japanese Pat. No. 51-117737 (a copolymer derived from bromobisphenol A which is used to flame-retard polyolefin); and Japanese Pat. No. 49-20155 (a bromoalkyl ether of polybrominated bisphenol A which is useful in flame-retarding polyolefins). Japanese Pat. No. 51-73548 discloses a thermoplastic polymer composition containing a halogenated bisphenylene ether fireproofing agent. Among the many agents encompassed within the broad generic teaching of the reference there is included the compound employed in the composition claimed herein. The reference does not, however, discuss flame retarding ABS plastics, nor does it teach the surprising compatibility of the fireproofing compound in ABS plastics or the improved impact resistance thereof.